It's always hard to find all the dings in a car and I like to find as many
as possible before priming and/or blocking.
What I do is after sanding and cleaning I park the car in my garage
and that nigt when it's really dark in the garage
I shine a flashlight over the panels just skimming them
with the light beam, it shows the flaws really well.
Any low spots I circle with a pencil, any high spots I mark with an "X"